Add configuration for git

- Add .config/git/config
  + Define aliases
  + Configure default behavior in various situations
  + Add user information with signing key
- Add .config/git/commit_msg_template.txt
- Add .config/git/ignore
- Integrate `git` aliases into the shell

.bashrc

@@ -66,7 +66,6 @@ fi
 
 
 # Enable tab completion
-
 if ! shopt -oq posix; then
     if [ -f /usr/share/bash-completion/bash_completion ]; then
         . /usr/share/bash-completion/bash_completion
@@ -74,65 +73,3 @@ if ! shopt -oq posix; then
         . /etc/bash_completion
     fi
 fi
-
-# Add tab completion for all aliases to commands with completion functions
-# (must come after bash completions have been set up)
-# Source: https://superuser.com/a/437508
-_alias_completion() {
-    local namespace="alias_completion"
-    # parse function based completion definitions, where capture group 2 => function and 3 => trigger
-    local compl_regex='complete( +[^ ]+)* -F ([^ ]+) ("[^"]+"|[^ ]+)'
-    # parse alias definitions, where capture group 1 => trigger, 2 => command, 3 => command arguments
-    local alias_regex="alias ([^=]+)='(\"[^\"]+\"|[^ ]+)(( +[^ ]+)*)'"
-    # create array of function completion triggers, keeping multi-word triggers together
-    eval "local completions=($(complete -p | sed -Ene "/$compl_regex/s//'\3'/p"))"
-    (( ${#completions[@]} == 0 )) && return 0
-    # create temporary file for wrapper functions and completions
-    rm -f "/tmp/${namespace}-*.tmp" # preliminary cleanup
-    local tmp_file; tmp_file="$(mktemp "/tmp/${namespace}-${RANDOM}XXX.tmp")" || return 1
-    local completion_loader; completion_loader="$(complete -p -D 2>/dev/null | sed -Ene 's/.* -F ([^ ]*).*/\1/p')"
-    # read in "<alias> '<aliased command>' '<command args>'" lines from defined aliases
-    local line; while read line; do
-        eval "local alias_tokens; alias_tokens=($line)" 2>/dev/null || continue # some alias arg patterns cause an eval parse error
-        local alias_name="${alias_tokens[0]}" alias_cmd="${alias_tokens[1]}" alias_args="${alias_tokens[2]# }"
-        # skip aliases to pipes, boolean control structures and other command lists
-        # (leveraging that eval errs out if $alias_args contains unquoted shell metacharacters)
-        eval "local alias_arg_words; alias_arg_words=($alias_args)" 2>/dev/null || continue
-        # avoid expanding wildcards
-        read -a alias_arg_words <<< "$alias_args"
-        # skip alias if there is no completion function triggered by the aliased command
-        if [[ ! " ${completions[*]} " =~ " $alias_cmd " ]]; then
-            if [[ -n "$completion_loader" ]]; then
-                # force loading of completions for the aliased command
-                eval "$completion_loader $alias_cmd"
-                # 124 means completion loader was successful
-                [[ $? -eq 124 ]] || continue
-                completions+=($alias_cmd)
-            else
-                continue
-            fi
-        fi
-        local new_completion="$(complete -p "$alias_cmd")"
-        # create a wrapper inserting the alias arguments if any
-        if [[ -n $alias_args ]]; then
-            local compl_func="${new_completion/#* -F /}"; compl_func="${compl_func%% *}"
-            # avoid recursive call loops by ignoring our own functions
-            if [[ "${compl_func#_$namespace::}" == $compl_func ]]; then
-                local compl_wrapper="_${namespace}::${alias_name}"
-                    echo "function $compl_wrapper {
-                        (( COMP_CWORD += ${#alias_arg_words[@]} ))
-                        COMP_WORDS=($alias_cmd $alias_args \${COMP_WORDS[@]:1})
-                        (( COMP_POINT -= \${#COMP_LINE} ))
-                        COMP_LINE=\${COMP_LINE/$alias_name/$alias_cmd $alias_args}
-                        (( COMP_POINT += \${#COMP_LINE} ))
-                        $compl_func
-                    }" >> "$tmp_file"
-                    new_completion="${new_completion/ -F $compl_func / -F $compl_wrapper }"
-            fi
-        fi
-        # replace completion trigger by alias
-        new_completion="${new_completion% *} $alias_name"
-        echo "$new_completion" >> "$tmp_file"
-    done < <(alias -p | sed -Ene "s/$alias_regex/\1 '\2' '\3'/p")
-    . "$tmp_file" && \rm -f "$tmp_file"
-}; _alias_completion